Method of making oval diaphragms



Feb. 6, 1951 .J. T. CLARK METHOD OF MAKING OVAL DIAPHRAGMS Filed July10, 1948 (6 .izzarieeys.

Tateuted Feb. 6, 1951 Ms'rnon or MAKING OVAL DIAPHRAGMS John T. Clark,Cicero, Ill. Application July 10, 1948, Serial No. 38,033

7 Claims.

This invention relates to a diaphragm and a spring structure and to amethod for making with parts in section and parts broken away;

Figure 2 is a plan view of the diaphragm of Figure 1;

Figure 3 is a sectional detail taken at line 33 of Figure 2 on anenlarged scale;

Figure 4 is a plan view of the spring structure before its inclusion inthe diaphragm;

Figure 5 is 'a plan view of two flat springs which form a part of thecomposite spring structure;

Figure 6 is an end elevation of one of the fiat spring members; and

Figure 7 is a plan View of a portion of a die.

Like parts are indicated by like characters throughout the specificationand the drawings.

As formed the spring structure includes a coil spring 1 which mayinitially be straight. In the final structure its ends are joined, as at2, to form an endless coil spring.

Two flat springs 3, 3 are formed generally in the shape indicated inFigure 5 and are biased to assume that shape. These flat spring membersare inserted in the coil spring I, and they are preferably sodimensioned with respect to the coil spring that their ends overlap, asshown at 4 in Figure 4.

After they have been inserted and the coil spring brought to the shapeof Figure 4, the ends of that spring are secured together at 2. The endsare secured together in this position either by threading theconvolutions of the two ends together, or otherwise.

After the spring structure has been made as shown in Figure 4, it islaid into the circular cavity or depression 5 in a mold or die 6. Acorresponding upper die member is used. This is not shown, as such diesare generally known in the art and the invention is not limited incarrying out the method to the use of any particular die.

With the spring structure in the round cavity 5, rubber is placed in themold and upon suitable treatment, such as the application of heat, thecomposite diaphragm is formed. The relatively thin section I is formedin the mold and the tubular enlargement 8 is also formed. ihis tubularenlargement 8 encloses the spring structure. As initially formed in themold, the entire device is round in plan. When the device is completedand removed from the mold, the springs move to the position shown inFigures 2 and i and assume a generally elliptical or oval shape.

The method of this invention provides a simple spring structure in whichan oval spring is formed, and it provides also a simple method formaking an oval diaphragm structure by the use of standard andconventional round die mechanisms. It is well known in the art to make adiaphragm round in plan. For many purposes a diaphragm of oval orelliptical plan is desirable and it is one of the objects of theinvention to provide a method for making a diaphragm of oval orelliptical plan by 'using the conventional molds of round plan,

Although I have shown an operative form of my invention, it will berecognized that many changes in the form, shape and arrangement of partscan be made without departing from the spirit of the invention, and myshowing is therefore to be taken as, in a sense, diagrammatic.

I claim:

1. The method of producing a generally elliptical spring structure anddiaphragm which comprises the following steps: forming a pair ofpartially elliptical springs, forming a coil spring, positioning saidsprings within said coil spring, and securing the ends of said coilspring together to form an endless coil spring, said partiallyelliptical springs being biased to assume an elliptical shape, placingsaid composite in a circular position, and molding rubber-like ma terialabout said spring structure within a mold, and thereafter removing saiddiaphragm and said spring from said mold and freeing said spring toassume an elliptical shape.

2. The method of producing a generally el1iptical spring structure anddiaphragm which comprises the following steps: forming a pair ofpartially elliptical springs, forming a coil spring, positioning saidsprings within said coil spring, and securing the ends or" said coilspring together to form an endless coil spring, said partiallyelliptical springs being biased to assume 7 spring, positioning saidflat springs within said coil spring, and securing the ends of said,coil spring together to form an endless coil spring, said partiallyelliptical springs being biased to assume an elliptical shape, placingsaid .comppsite spring in a circular position, and forming rubber-likematerial about said spring stnuctune, and thereafter freeing said springto assume an elliptical shape.

4. The method of producing a generally ellipe tical spring structure and{diaphragm which com,- prises the tollowing steps: forming a pair ofpartially elliptical springs, forming .a .coil spring positionin saidsprings within said coil spring withitheir ends overlapping, andsecuring the ends of said coil spring together to form an endless coilspring, said partially elliptical springs being biased to assume anelliptical shape, placing said composite spring in a circular shape, andforming rubber-like material about ,said spring structure, andthereafter freeing said spring to assume an elliptical shape.

5. The method of producing ,a generally ,elliptical spring structure anddiaphragm which ,comprises the following steps: forminga ,pa-irof fiat,partially elliptical springs, iorming a coil spring, positioning saidflat springs within :said ,coil spring. securing the .ends of said ,coilspring together to ,-for-m an endless ,coil spring, said partiallyelliptical springs being biased {to assume an elliptical shape, ,placingsaid composite spring material about said spring structure, and moldingan integral diaphragm across the space bounded by said spring structure,thereafter freeing said spring to assume an elliptical shape.

6. The method of producing a generally elliptical spring structure anddiaphragm which comprises the following steps: forming a pair of flat,

partially elliptical springs, forming a coil spring, positioning saidfl-at spring within said coil sprin with their ends ouerlapping, andsecuring the ends of said ,coil spring together to form an endless coilspring, said partially elliptical springs being biased to assume anelliptical shape, placing said composite spring in a circular position,

and forming rubber-like material about said spring structure, andthereafter freeing said spring to assume an elliptical shape.

'7. The method of producing a generally ellip tical spring structure anddiaphragm which comprises the following steps: forming a pair of flat,partially elliptical springs, forming a coil spring. positioning saidfiat springs within said coil spring with their ends overlapping, and,secur ng REFERENQES o rnn The ifollowing references are of record in:tl e file of this patent:

UNITED STATES PATENTS Number Name Date 1,163,653 Harvey dune 17, 1,9302,101,255 Hay Dec. 7,, 2,294,589 Waterbury Sept. 1, i942

1. THE METHOD OF PRODUCING A GENERALLY ELLIPTICAL SPRING STRUCTURE ANDDIAPHRAGM WHICH COMPRISES THE FOLLOWING STEPS: FORMING A PAIR OFPARTIALLY ELLIPTICAL SPRINGS, FORMING A COIL SPRING, POSITIONING SAIDSPRINGS WITHIN SAID COIL SPRING,, AND SECURING THE ENDS OF SAID COILSPRING TOGETHER TO FORM AN ENDLESS COIL SPRING, SAID PARTIALLYELLIPTICAL SPRINGS BEING BIASED TO ASSUME AN